1. Field of the Invention
The present invention relates to a cooling and dust collecting apparatus for machine tool which cools a cutter and exhausts cutting chips.
2. Description of the Related Art
Thus far, various types of cooling and dust collecting apparatuses for machine tools have been proposed. For example, in Japanese Patent Laid-Open Publication No. 58-59746, a cooling and dust collecting apparatus is disclosed. In the apparatus, a drill is surrounded by a hood. By spraying mist of a cutting oil toward the center of the drill from four positions, the drill is cooled. In addition, by sucking the mist of cutting oil and cutting chips in the hood, they are exhausted from a dust collecting duct.
Moreover, in Japanese Patent Laid Open Publication Nos. 63-300807 and 3-3713, pressure foot for printed circuit board drilling machines are disclosed. A pressure foot is connected to a cutting chip sucking device through a hose so as to keep the inside of the pressure foot in a negative pressure state. In addition, compressed air is horizontally blown from the vicinity of the front end of the pressure foot in the tangent direction of the drill. The compressed air expands in the pressure foot in heat resisting state, thereby sharply lowering the temperature therein and blowing cutting chips. Thus, the cutting chips can be exhausted to the cutting chip sucking device.
However, in the above-mentioned cooling and dust collecting apparatuses for machine tools, since mist of cutting oil or compressed air is blown to a cutter in nearly horizontal direction, a portion of the cutter which is exposed is cooled, whereas a portion which is hidden in a workpiece is not cooled. In addition, cutting chips which are caught in a hole or groove are not exhausted.
Moreover, causes of heating of the cutter are cutting heat and heat conducted from a driving portion of the cutter. In the conventional cooling and dust collecting apparatuses for machine tools, the heat conducted from the driving portion of the cutter is not considered. Thus, the cutter is not satisfactorily cooled.
Therefore, an object of the present invention is to provide a cooling and dust collecting apparatus for machine tool which cools both portions of a cutter which are exposed and hidden in a workpiece, protects heat of a cutter driving portion from being conducted to the cutter, and exhausts cutting chips caught in a hole or groove.